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Rock&Roll Firebird
08-19-2014, 03:05 PM
Any idea where to start when a horn is not working but the horn itself passed the direct-power test?

simplyconnected
08-19-2014, 03:29 PM
Start by taking two (#3 Phillips head) bolts loose on your steering column, the ones just above your knees, and pull the column straight up to your chest without turning it. - Dave

jopizz
08-19-2014, 05:06 PM
When you checked the horn did you use the relay or just put power to the horn. The relay is on the front driver side firewall down by the radiator.

John

Rock&Roll Firebird
08-19-2014, 05:46 PM
When you checked the horn did you use the relay or just put power to the horn. The relay is on the front driver side firewall down by the radiator.

John

Actually I did not test the horn just yet. Do I need to put the relay between the battery and the horn when testing ? If so, how to connect the relay to test it?

jopizz
08-19-2014, 07:01 PM
You don't need the relay to test the horn itself if you are just going to put 12V to it but you need the relay for it to work from the horn button on the steering wheel. Are you saying that the relay is not there or not connected? The relay has three posts. One (middle) should have 12V all the time. One end post goes to the horn button and the other post goes to the horn. To test the relay you will need either a test light or a voltmeter.

John

Tbird1044
08-19-2014, 10:43 PM
As already stated, first check the horn to see if it works by putting 12v directly to the horn connector. If the horn works, proceed. Locate the horn relay and identify the 3 wires to the relay. One 12v +, one to the horn contact in the steering column, and one wire going to the horn contacts. If you put a ground connection to the wire going to the steering column, the horn should sound. If it doesn't, the relay is bad. If the horns work, then trying adjusting the steering column as Dave already stated. If that still doesn't work, the horn assembly itself is a real piece of work on these cars. There are spacers and insulators used where the horn ring is assembled to the steering wheel. I think there is a write up in the TRL on how to assemble the horn ring to get it to work.
Nyles

Rock&Roll Firebird
08-20-2014, 02:34 AM
Thank you guys, with these informations it should be easy to find the issue.

simplyconnected
08-20-2014, 03:45 AM
Horns take a lot of current, so Ford used a relay to allow a small current to control a huge current.

It is important to note that the horn relay does not use the case as a ground.

The wiring diagram shows, power comes from the Voltage Regulator 'B' post and it connects to the center post on the Horn Relay. Inside the center post, +12 connects to one side of the coil AND one side of the contact. The other side of the coil comes out the left hand terminal and goes to your horn ring on the steering wheel. When pressed, the horn ring completes a path to ground which energizes the Horn Relay's coil. The closed Horn Relay contact sends +12 power out the Right Hand terminal to your Horns.

Sooooooo... if you simply ground the left hand terminal of the Horn Relay, it will energize the coil and cause your horns to honk.

There is no fuse protection in this circuit because Ford wanted to save money, the power wire is very short and if the other coil wire shorts to ground, the horns simply honk. - Dave